Reuse of lead glass sludge in the fabrication of thermally insulating foamed glass with outstanding properties and high Pb-stabilization.

This study represents the sustainable/safe consumption of lead glass sludge (LGS) in the fabrication of thermally insulating foamed glass via sintering (750-950º C) and chlorination processes. The impact of selected additives including calcium chloride (CaCl2) and sodium hydroxide (NaOH) on the foaming efficiency and Pb-stabilization has been deeply investigated. LGS is mainly lead silicate material with considerable content of calcium carbonate, which acts as foaming agent during sintering process. The newly developed foamed-materials exhibited thermal conductivity of 0.054-0.136 W/m.K, density of 0.23-1.10 g/cm3, porosity of 63.3-92.6%, and compressive strength of 0.10-2.69 MPa. X-ray diffraction proved that the immobilization mechanism was attributed to the transformation of free Pb within LGS into insoluble ganomalite Pb9Ca5MnSi9O33 phase. Adding NaOH enhanced the foaming process accompanied by a significant reduction in Pb-leaching. Incorporating CaCl2 has resulted in a retardation in Pb-leaching, which associated with Pb-stabilization and Pb-vaporization. In an attempt to reduce CO2-emission, the potential use of alkali-rich-wastewater (AW) as eco-friendly alkali source in lieu of NaOH was studied. Regardless of the variation in Pb-concentrations in leachates, all samples recorded Pb-concentrations lower than the safe limit (≤ 5 mg/l), achieving Pb-immobilization of 95.98-99.87%. The significantly reduced thermal conductivity and enhanced Pb-immobilization efficiency along with the reasonable compressive strength summarize the major innovation presented in this study.

In silico assessment of potential leads identified from Bauhinia rufescens Lam. as α-glucosidase and α-amylase inhibitors.

INTRODUCTION: Natural products play a pivotal role in innovative drug discovery by providing structural leads for the development of new therapeutic agents against various diseases.The present study aims to focus on the in silico assessment of the therapeutic potential of antidiabetic phytoconstituents which were identified and isolated from the extracts of Bauhinia rufescens Lam, a medicinal plant traditionally used for various pharmacotherapeutic purposes. METHOD: The physicochemical and pharmacokinetic parameters of the previously isolated thirty eight compounds were predicted using SwissADME web tool whereas OSIRIS Property Explorer was used for toxicity risk assessment and drug- likeliness. Twelve compounds were selected for docking on human α-glucosidase and α-amylaseenzymes using Autodock 4.0 software. Furthermore, the active extract was in vivo tested for the antidiabetic activity and then identified usingTLC bioautographic method. RESULTS AND DISCUSSION: Eriodictyol was found to have the highest potential as an inhibitor against α-amylase with binding energy of -9.92 kcal/mol. Rutin was the most potent against α-glucosidase with binding energy of-9.15 kcal/mol. A considerable number of hydrogen bonds and hydrophobic interactions were computed between the compounds and the enzymes thereby making them energetically favorable and suggesting inhibition of these two enzymes as a plausible molecular mechanism for their antidiabetic effect. CONCLUSION: These two flavonoids could therefore be used as potential leads for structure- based design of new effective hypoglycemic agents.

Bio-removal of Pb, Cu, and Ni from solutions as nano-carbonates using a plant-derived urease enzyme-urea mixture.

This study focuses on utilizing a plant-derived urease enzyme (PDUE)-urea mixture to remove heavy metals from water as constituents of nano-carbonate minerals. The bio-removal process was conducted by individually mixing PbCl2, CuCl2, and NiCl2 solutions with a PDUE-urea mixture, followed by incubation for 24 h at 23 ± 2 °C. The preliminary results revealed that the proposed method exhibited high Pb removal efficiency (˃ 99%) in a short time (8 h); meanwhile, moderate Cu and Ni removal efficiencies (67.91% and 58.49%, respectively) were obtained at the same incubation time. The concentration of heavy metals (50-200 mM) had an insignificant effect on the bio-removal rate, indicating that the PDUE-urea mixture is highly effective for the removal of heavy metals at different concentrations. The bio-removal process involved the transformation of soluble heavy metals into insoluble carbonate materials. A spherically shaped nano-cerussite (4-15 nm), a malachite hexahydrate nanosheet (thickness 8 nm), and an ultrafine micro-hellyerite (thickness 0.3 µm) were the main minerals produced by the Pb, Cu, and Ni bio-removal processes, respectively. As a beneficial application, nano-cerussite was used as an additive in an alkali-activated slag/ceramic waste-based geopolymeric coating. A preliminary study proved that increasing the nano-cerussite content enhanced the resistance of the geopolymeric coating to sulfur-oxidizing bacteria, which is detrimental to normal concrete, particularly in sewer systems.